Armature insulation and method of molding same



Feb. 25, 1941. I c. w. STUDER ARMATURE INSULATION AND METHOD OF HOLDiNQ SAME Filed on. 25, 1937 5 Sheets- Shept 1 \VLI I Clair msz ATTORNEY Feb. 25, 1941. c. w. sTuDER ARMATURE INSULATION AND METHOD 0? MOLDING 5MB Filed Oct. 25, 1937 sspmta-sh t z' & I \A 5 2 V w 6 A 4m. NN

Feb. 25, 1941. c w STUDER 2,232,812

' ARMATURE INSULATION AND METHOD 01- MOLDING sum med Oct. 25. 19s"! 5 she y fisheet s @EEEEE.

I v INVENT R Clair W Siudezr Feb. 25,1941. c TU 2,232,812

ARMATURE INSULATION AND HETHOD Q F HOLDING SAME v Filed Oct. 25, 1937 s Sheets-Sheet 4 & %%F 4 A Feb. 25, 1941. C w STUDER 2,232,812

ARMATURE INSULATION AND METHOD OF MOLDING SAME Filed Oct. 25, 1937 5 Sheets-Sheet 5 I IV INVENTOR Clair WStudeI' ATTORNEY Patented Feb. 25, 1941 UNITED STATES ARMATURE INSULATION AND METHOD OF MOLDING SAME Clair W. Studer, North Canton, Ohio, assignor to The Hoover Company, North Canton, Ohio, a

corporation of Ohio Application October 25, 1937, Serial No. 170,793

16 Claim.

This invention relates to armature insulation and to methods and apparatus for molding the same.

An object of the invention is to provide armature insulation'having the bushings, end plates and slot liners secured together. A further object is to provide armature insulation completely enclosing the armature stack whereby the windings will not contact the metal laminae.

10 Another object of the invention is to mold armature insulation out of suitable electric insulating molding material, such as cellulose acetate. Another'object is to provide a method for molding the armature insulation. A further object is to 15 provide apparatus for carrying out the molding process. Other objects and advantages oi the invention will be apparent from the specification and drawings, wherein:

Fig. 1 is anelevational view partly in section 2 oi a completed armature;

Fig. 2 is a sectional perspective view of a parted mold for molding" a bushing, end plate and slot liners forming part of the armature insula- -tion;

\ Fig. 3 is a section through the mold in closed position; v

Fig; 4 is a sectional perspective view of another parted mold, for molding the other bushing and end plate forming the other part of the ar- 30 mature insulation; 1

' Fig. 5 is a section through the mold in closed position;

,Fig. 6 is a sectional perspective view showing another parted mold for sealing the two molded in- 35 sulators together to form the completed armature insulation; 1 v Fig. '7 is sectional view of the mold in closed position;

Fig. 8 is a sectional'perspective view oi an- 40 other embodiment of the invention, showing a parted mold for molding the slotliners, end plates and bushings as a unit about the armature stack;

Fig. 9 is a section of the molding apparatus'in 5 closed position;

Fig. 10 is a sectional" perspective view of another embodiment of the invention, showing a parted mold for molding a bushing, end plates and slot liners forming one-half the completed 50 insulation;

Fig. 11 is a section of the mold in closed position: and

Fig. 12 is a sectional perspective view show ing the method of assembling the duplicate 55 molded insulators shown in Fig. 10 about'the armature stack to completely insulate the armature.

One embodiment of the invention is shown in Figures 1 through '7 and comprises an armature insulation molded in two parts, one insulator l0 shown in detail in Fig. 2, and another insulator ll shown in detail in Fig. 4, the two insulators l0 and H being sealed together to provide the armature insulation shown in Fig. 6. The armature insulation may be molded out of a suit- 10 able thermo-plastic molding compound, such ,as cellulose acetate. The molded insulator l0 comprises a bushing l2, a spider or end plate 13 provided with teeth l'4 having their marginal edges l5 integral with slot liners l1. The bushings I2 15 accommodates the armature shaft l3, and the end plate I3 is disposed along the lower outer lamination 22 of the armature stack l9, while the slot liners 11 are disposed in the laminae slots and extend slightly beyond the upper outer 20 lamination 23 of the stack IS. The other insulator ll comprises a bushing 24, a spider or end plate 25 provided with spaced teeth 26 which are adapted to fit in the openings 21 formed between the adjacent slot liners I! as clearly 25 shown in Fig. 6.

The apparatus for molding the insulator l0 comprises a base member 30 provided with a cylindrical cavity 3| communicating with an iniection port 32 extending to the lower edge of the 30 base 3|! and terminating in a depression 33 which is adapted to receive the injecting nozzle for nserting the molding compound into the molding apparatus. Above the base 30 isa molding member 34 adapted to be detachably secured to-the 35 base 30 by means of screws 35 disposed in openlugs 37. Extending through the mold member 34 is a cavity 38 in which are spaced annularly arranged projections 39 tapered inwardly toward the center of the'cavity and defining therebe- 4 tween recesses 40. Adapted to be removably disposed upon the mold member 34 is a top plate 4| provided with a plurality of guide pins 42 for insertion in the openings 36 in the mold member 34. Depending from the molding member M is 5 a projection provided with a plurality of spaced annularly arranged teeth 44 which define therebetween slots 45 adapted to receive the projecting teeth 39 in the mold member 34 to form the slot liners ll of the insulator ill. Depending from the projection 43 is a cylindrical member 46 adapted to be disposed in the cavity 3| in the lower mold member 30 to form the bushin2l2.

T0 car y-out the molding process the mold is assembled with the guide pins 42 disposed in the openings 36 to position the member 46 in spaced relation with respect to the cavity 3| to define the bushing I2, and the teeth 44 are disposed in the slots 40 in spaced relation with respect to the teeth 39 to form the molded slot liners 11. When the molding apparatus is properly assembled there will be a vacant space between the lower surface 48 of the projection 43 and the upper surface 49 of the molding member 20 to form the spider I3. The assembled mold is kept at a relatively cool temperature and the thermoplastic molding compound, such as cellulose acetate, is heated to a suitable temperature and then injected through the port 32 into the mold to form the bushing I2, spider I3 and slot liners II. During the molding operation the mold is kept relatively cold which causes the molding material to solidify. After the molding compound has solidified, the mold is parted and pressure exerted on the ejector pins 50 to remove the insulator from the upper mold member 4I. As a result of the molding process a sprue or gate 5| is formed in the injection port 32 which must be removed from the bushing I2.

The apparatus for molding the insu1ator II comprises a base mold member 55 and a top mold member 56,- the former being provided with-a cavity 51 communicating at one end with an in jection port 58 and at the opposite end terminating in an annular projection 52 extending above the surface 66 of the base member 55. The an nuiar projection 52 is provided with spaced radially extending projections 60 defining therebetween slots 6| which are adapted to form the teeth 26 of the spider 25. The mold member 55 is provided with a plurality of openings 62 ior the reception of guide pins 63 depending from the upper member 56, the latter being provided with an annular recess 64 defined by a shoulder 65 which is adapted to snugly engage the periphery 81 of the projection 52 to form the dimeter of the spider 25. Depending from the upper mold member 56 is a member 88 which is adapted to be disposed in spaced relation with the wall of the cavity 51 to form the bushing 24.

In molding the insulator I I the upper mold member 58 is placed upon the lower member 55 with the guide pins 63 in the openings 62 which properly positions the mold members with respect-to each other, and thereafter the molding material, which may be a thermo-plastic compound such as cellulose acetate, is injected through the injection port 58 into the chamber 51 and between the cooperating molding members to form the spider 25 and its teeth 26 and the bushing 24. In order to remove the molded insulator from the member 55 pressure is exerted on the ejector pins 69.

The insulators I0 and II are then assembled to form a unitary armature insulation. The apparatus for uniting these two insulators is shown in Figures 6 and 7 and comprises a fixture I5 provided with a bore I6 communicating with the cavity 11 adapted to receive the laminae 2I of the armature, and the peripheral wall of the cavity is provided with guide pins II which are adapted to be disposed between the narrow slots I9 between the adjacent teeth of the laminae 2I to properly position the latter in the lower fixture I5. Suitable guide openings 10 are provided in the lower fixture I5 to receive the guide pins inthe upper fixture 6| which is provided with a depending projection 82 having its lower surface provided with substantially V shaped notches 83 their outer ends with a reduced portion and a plurality oi projections 84, the inclined walls 92 of the depressions 83 being adapted to engage the free ends 90 of the slot liners IT to swedge the latter onto the teeth 2fi oi the spider 25 to seal the insulators together.

The method of sealing together the insulators I0 and II comprises arranging the insulator ID on the armature shaft I8 with the slot liners Il disposed in the winding slots 20, the slot liners I'I being of such length as to extend beyond the end lamination 23 of the armature stack, and thereafter sliding the insulator II along the armature shaft I8 until the teeth 26 of the insulator II are disposed in the openings 2'! between the adjacent slot liners IT, as indicated in Fig. 6.

The assembled insulators I0 and II and the armature stack I9 and shaft I8 are then placed as a unit in the lower fixture I5 with the bushing I2 in the opening it, and the spider I3 resting on the bottom 9i of the cavity 'I'l, the guide pins 78 being disposed between the narrow slots I9 formed between the teeth of the laminae to properly position the armature stack in the lower fix ture 15. The upper fixture BI is placed upon the lower fixture I5 with the guide pins 80 in the openings III to guide the inclined walls 92 of the V-shaped slots 83 into engagement with the corners 90 of the slot liners IT, and the bushing 24 of the insulator I I is disposed in the opening 93 of the upper fixtiue BI. Heat is then applied to the upper fixture or sealing member Iii to heat the inclined walls 92 of the V-shapecl notches 83 to swedge the ends 90 oi the slot liners IT to the marginal edges oi" the spider teeth 25, and thus seal the insulators I0 and II together. In order to remove the molded insulated armature from the mold, the upper fixture 8| is slidably removed and thereafter the molded armature is separated from the lower fixture 15.

Another embodiment of the invention is shown in Figures 8 and 9. In this modification the armature insulation is molded in one piece directly onto the armature stack and the shaft. The armature insulation comprises spiders IOI and I02 respectively provided with bushings I05 and I06 arranged about the armature shaft I01 and teeth I03 and I04 molded on the armature stack I09, the slot liners 98 molded in the laminae slots I08.

The apparatus for molding the insulation directly on to the armature includes a lower fix ture I I0 provided with a bore II I communicating with a cavity H2, and projecting from the annular wall I I3 of the cavity is a plurality of spaced annularly arranged projections I I4 provided at II6 adapted to accommodate the narrow slots 99 on the armature stack I09, and the projections II4 are tapered inwardly towards the armature shaft I01 and are substantially complementary to the enlarged laminae slots I08 for registry with the same. Projecting from the bottom wall I00 of the cavity H2 is an annular shoulder Ill, and the upper part of the cavity H2 is enlarged to provide another annular shoulder III! which lies flush with the upper surface of the projections H4. The lower fixture IIO has a plurality oi guide openings I20 for the reception oi the guide pins I2I in the upper fixture I22 which is provided with a central opening I23 adapted to accommodate the armature shaft I01 and the molded bushing I06, and the opening I2? terminates in an annular depending projection I24 provided with spaced annularly arranged depending arcuate lugs I26 on the surface I25 of the projection 124. The depending lugs m are adapted to fit between the adjacent reduced portions H6 of I the projections H4 of the lower fixture H0, and

the margin I21 of the projection I24 rests upon the shoulder II8 of the lower fixture IIO.

In order to carry out the molding process, the unwound armature stack I 09 and shaft I'0'I are inserted as a unit in the lower fixture IIO so that the molding cores or projections H4 are disposed in spaced relation in the laminae slots I08 to form the slot liners 98, the lower end of the laminae resting on the annular shoulder ill to provide a vacant space for molding the spider I! and the shaft I0i rigidly supported in the reduced portion of the bore I I I. The upper fixture M2 is then placed upon the lower fixture I I0 with the guide pins H25 in the guide openings I20 to properly position the lugs I26 between the adjacent reduced portions H6 of the projections i I4, and the marginal edge I21 of the projection I24 rests upon the shoulder H8.

The molding compound which may be of suitable thermoplastic material, such as cellulose acetate, is then injected through the injection port I3I into the mold about the cores 4 and the armature stack and shaft to mold the insulation directly onto the laminations of the armature. When the molding operation is completed and the cellulose acetate has solidified, the mold is parted and the armature removed. Thereafter the sprue I32 formed during the injectionmolding process is removed From the foregoing it will be perceived that this modification provides an. armature insulation that is molded as a unit about the rotor and that the bushings, spiders and slot liners are molded directly onto the armature to provide an insulation which completely encloses the armature stack.

Another embodiment of the invention is shown in Figures 10 to 12 and comprises armature insu lation formed in two duplicate partsi35 and IE6, each part having a bushing MD, a spider Idi. provided with teeth I43 integrally formed with slot liners 544 which extend only one-half the length of the winding slots I45 in the armature stackv it'i.

The apparatus for molding the insulators I35 and use is similar to that shown in Figures 2 and 3, the only distinction being in the apparatus for forming the slot liners I44 are substantially one-half the length of the laminae slots I45. In

this modification the molding apparatus comprises a base I50 provided with a cavity II communicating with an injection port I52. Detachably supported in the base E50, by screws I53, is a mold member I54 provided with a cavity I55 in which are spaced annularly arranged projections i5ii defining slots I5'I substantially one-half the length .of the laminae slots I45. An upper mold member 65% is provided with a projection I59 having radially extending teeth I60 adapted to be inserted in the slots I 57 to form one-half the length of the slot liners. Depending from the projection I59 is a member IIiI for insertion in the cavity I5I to form the bushings I40.

The molding process to mold the insulators I35 and I35 is carried out in the manner described in connection with the first embodiment.

In order to assemble the armature insulators on the armature stack I31 and shaft I64, the molded insulators I35 and I36 are moved along the shaft I54 and the molded slot liners I44 inserted into the laminae slots I45, the free ends I'I0 of the slot liners Md meeting substantially midway of the laminae slots I45. If desired, the slot liners I 44 may be of such length as to overlap slightly at their points of contact. The armature is then wound, impregnated with varnish and baked. The temperature at which the varnish is baked tends to soften the insulators and the free ends I will be sealed together.

I claim:

1. A rotor, comprising a core having a plurality of winding slots and supported on a shaft, and molded insulation lining said core slots and covering the opposite ends of said core and said shaft adjacent said opposite ends, said molded slot liners having openings to receive the winding for said rotor.

2. A rotor, comprising a core having a plurality of winding slots and supported on a shaft, a moldliners and a spider, said slot liners lining said winding slots and said spider covering an end of said core, and a molded insulator including another spider covering the other end of said core and sealed to said slot liners.

4. A rotor, comprising a core having a plurality of winding slots and supported on a shaft, and a single mass of insulation lining said winding slots and extending outwardly therefrom to cover the opposite ends of said core and said shaft adjacent said opposite ends, said molded mass of insulation having openings for receiving the winding for said rotor.

5. A rotor, comprising a core provided with winding slots, and a single mass of insulation molded about said core, lining said winding slots and covering the opposite ends-of said core, said molded mass of insulation having openings for receiving the winding for said rotor.

6. A rotor, comprising a core having a plurality of winding slots and supported on a shaft, and a two part insulator, each part including slot liners lining a portion of the length of said windingslots, and a spider covering an end of said core, and a bushing disposed about said shaft adjacent each spider.

7. A rotor, comprising a core provided with winding slots, and a two'part insulator each part including slot liners lining a portion of the length of said winding slots, and a spider covering an end of said core.

8. The method of insulating a rotor having a core provided with winding slots, which consists of molding a one piece insulator including a spider and slot liners, molding a separate spider, arranging said insulator about said core with its slot liners lining said winding slots and its spider covering an end of said core, arranging said sepa: rate spider about said core covering another and of said core, and sealing said slot liners to said separate spider.

9. The method of insulating a rotor having a core provided with winding slots and supported on a shaft, which consists of molding a one piece insulator including a bushing, spider and slot liners, molding in one piece another insulator including a bushing and spider, arranging the first mentioned insulator on said core the molded slot liners lining said winding slots, the spider covering and end of said core and the bushing disposed about said shaft, arranging said other insulator on said core with its spider covering the other end and its bushing about. said shaft, and then sealing said slot liners to the spider oi said another insulator.

10. The method of insulating a rotor having a core provided with winding slots, which comprises molding in duplicate a pair of insulators each having a spider and slot liners, said spiders corresponding to the flat contour of the end of said core, and said slot liners corresponding to the contour 01' said winding slots and substantially one-half the length of said slots, and assembling said insulators on said core with said slot liners lining said core slots and said spiders covering the ends of said core.

11. The method of insulating a rotor having a core provided with winding slots, which comprises forming in duplicate a pair of insulators each having a bushing, a spider and slot liners, said bushings corresponding to the contour of the rotor shaft, said spiders corresponding to the flat contour of the ends or said core, and said slot liners corresponding to the contour 01 said winding slots and substantially one-half the end of said slots, and assembling said insulators on said core and shaft with said slot liners lining said winding slots, each spider covering an end of said core and said bushings disposed about said rotor shaft.

12. An armature, comprising a core having a plurality of winding slots, pre-molded insulation lining said slots and covering the outer surfaces of the opposite ends of said core, said pre-molded insulation providing open-mouth insulation lined winding slots, and a winding disposed in and wound about said pre molded insulated slot liners and. about said pre-molded insulation covering the outer surfaces of said opposite ends of said core.

13. An unwound rotor, comprising a core having a plurality of slots, molded insulation lining said slots and covering the outer surfaces of the opposite ends oi! said core, said molded insulation having open winding slots for receiving the winding for said rotor, whereby said rotor may be wound.

14. Insulation for an unwound rotor having a plurality of slots, comprising molded insulation lining said slots and the outer surfaces at the opposite ends of said rotor, said molded insulation having open winding slots for receiving the winding for said rotor, whereby the latter may be wound.

15. An unwound rotor, comprising a core supported on a shaft and having a plurality of slots, and molded insulation lining said slots and covering the outer surfaces of the opposite ends of said rotor and the shaft adjacent said opposite ends of said rotor, said molded insulation having open winding slots for receiving the winding for said rotor, whereby the latter may be wound.

16. In a rotor, a core having a plurality of slots, and molded insulation lining said slots, said molded insulation having open winding slots lining said slots of said rotor for receiving the winding for said rotor, whereby the rotor winding may be inserted in said insulated open winding slots to wind said rotor.

CLAIR W. STUDER. 

